Dye developers which are non-reversibly spectrally shifted by alkaline hydrolysis in color diffusion transfer processes and elements

ABSTRACT

TRANSFER IMAGES IN COLOR ARE FORMED BY EXPOSING A PHOTOSENSITIVE ELEMENT CONTAINING A SILVER HALIDE EMULSION AND A MONO OR DISAZO DYE WHICH CONTAINS NOT LESS THAN ONE OR MORE THAN TWO GROUPS SELECTED FROM THE GROUP REPRESENTED BY THE FORMULAE.   -N=N-(CH2)2-OOC-CH2-O-R   R-O-CH2-COO-(CH2)2-N=N-(CH2)2-OOC-CH2-O-R   WHEREIN R IS A LOWER ALKYL GROUP, SAID DYES ALSO CONTAINING NOT LESS THAN ONE NOR MORE THAN TWO DIHYDROXYPHENYL SILVER HALIDE DEVELOPING RADICALS; PERMEATING THE PHOTOSENSITIVE ELEMENT WITH AN AQUEOUS ALKALINE PROCESSING COMPOSITION, AND DEACYLATION OF THE   -OOC-CH2-O-R   GROUPS BY HYDROLYSIS TO PROVIDE HYDROXYL GROUPS, THEREBY PROVIDING A NON-REVERSIBLE BATHOCHROMIC SHIFT OF THE SPECTRAL ABSORPTION CHARACTERISTICS OF DYE; IMMOBILIZING THE DYE AS A RESULT OF THE DEVELOPMENT OF THE EXPOSED AREAS OF THE EMULSION; AND TRANSFERRING, BY DIFFUSION, AT LEAST A PORTION OF THE IMAGEWISE DISTRIBUTION OF DYES TO A SUPERPOSED IMAGE RECEIVING LAYER TO PROVIDE A POSITIVE DYE IMAGE THEREIN.

M y 8, 1971 R. F. w. CIECIUCH ETAL 3,579,334

'DYE DEVELOPERS WHICH ARE NQN-REVERSIBLY SPECTRALLY SI'IIFTED BYALKALINE I'IYDROLYSIS IN COLOR DIFFUSION I TRANSFER PROCESSES ANDELEMENTS Filed Aug. 30, 1968 SUPPORT IMAGE-RECEIVING LAYER RUPTURABLECONTAINER HOLDING A PROCESSING COMPOSITION 22 SILVER HALIDE EMULSIONLAYER AND ASSOCIATED TEMPORARILY SHIFTED DYE DEVELOPER SUPPORT SUPPORTIMAGE-RECEIVING LAYER YER OF PROCESSING COMPOSITION 44 LUE-SENSITIVEEMULSION AND IATED YELLOW DYE DEVELOPER SENSITIVE EMULSION ANDASSOCIATED TEMPORARILY SHIFTED MAGENTA DYE DEVELOPER RED-SENSITIVEEMULSION AND ASSOCIATED CYAN DYE DEVELOPER F I G 2 SUPPORT INVENTORS M F14 26M BY Wonddm filwzmgm/rjlm 772. 59a ATTORNEYS United States PatentOlfice US. Cl. 96--29 13 Claims ABSTRACT OF THE DISCLOSURE Transferimages in color are formed by exposing a photosensitive elementcontaining a silver halide emulsion and a mono or disazo dye whichcontains not less than one or more than two groups selected from thegroup represented by the formulae.

wherein R is a lower alkyl group, said dyes also containing not lessthan one nor more than two dihydroxyphenyl silver halide developingradicals; permeating the photosensitive element with an aqueous alkalineprocessing composition, and deacylation of the groups by hydrolysis toprovide hydroxyl groups, thereby providing a non-reversible bathochromicshift of the spectral absorption characteristics of dye; immobilizingthe dye as a result of the development of the exposed areas of theemulsion; and transferring, by diifusion, at least a portion of theimagewise distribution of dyes to a superposed image receiving layer toprovide a positive dye image therein.

This invention relates to photography and, more particularly, to animprovement in photographic diifusiontransfer reversal processes forobtaining color images.

It has been proposed, in US. Pat No. 2,983,606, issued May 9, 1961, toform color images by dilfusion-transfer reversal processes utilizing dyedevelopers. In a process of this type, a photosensitive elementcontaining a dye developer and a silver halide emulsion is exposed andwetted by a liquid processing composition, for example, by immersion,coating, spraying, flowing, etc., in the dark, and the exposedphotosensitive element is superposed prior to, during or after wetting,on a sheetlike support element which may be utilized as animage-receiving element. In a preferred embodiment, the liquidprocessing 3,579,334 Patented May 18, 1971 composition is applied to thephotosensitive element in a substantially uniform layer as thephotosensitive element is brought into superposed relationship with theimagereceiving layer. The liquid processing composition permeates theemulsion to initiate development of the latent image contained therein.The dye developer is immobilized or precipitated in exposed areas as aconsequence of the development of the latent image. This immobilizationis apparently, at least in part, due to a change in the solubilitycharacteristics of the dye developer upon oxidation and especially asregards its solubility in alkaline solution. It may also be due in partto a tanning effect on the emulsion by oxidized developing agent, and inpart to a localized exhaustion of alkali as a result of development. Inunexposed and partially exposed areas of the emulsion, the dye developeris unreacted and diifusible and thus provides an imagewise distributionof unoxidized dye developer dissolved in the liquid processingcomposition, as a function of the point-to-point degree of exposure ofthe silver halide emulsion. At least part of this imagewise distributionof unoxidized dye developer is transferred, by imbibition, to asuperposed image-receiv ing layer or element, said transfersubstantially excluding oxidized dye developer. Under certainconditions, the layer of liquid processing composition may be utilizedas the image-receiving layer. The image-receiving element receives adepthwise diffusion, from the developed emulsion, of unoxidized dyedeveloper without appreciably disturbing the imagewise distributionthereof to provide the reversed or positive color image of the developedimage. The image-receiving element may contain agents adapted to mordantor otherwise fix the diffused, unoxidized dye developer. If the color ofthe transferred dye developer is affected by changes in the pH of theimage-receiving element, this pH may be adjusted in accordance withwell-known techniques to provide a pH aifording the desired color. Thedesired positive image is revealed by stripping the image-receivinglayer from the photosensitive element at the end of a suitableimbibition period.

The dye developers, as noted above, are compounds which contain, in thesame molecule, both the chromophoric system of a dye and also a silverhalide developing function. By a silver halide developing function ismeant a grouping adapted to develop exposed silver halide. A preferredsilver halide development function is a hydroquinonyl group. Othersuitable developing functions include ortho-dihydroxyphenyl and orthoandpara-amino substituted hydroxyphenyl groups. In general, the developmentfunction includes a benzenoid developing function, that is, an aromaticdeveloping group which forms quinonoid or quinone substances whenoxidized.

The preferred dye developers possess the characteristics of relativelyhigh absorption of actinic radiation over a desired segment of thespectral range as well as substantially no absorption over the remainingportion of the spectrum. For example, in a diffusion-transfer re versalprocess for three-color substractive photography, the preferred dyedevelopers utilized should comprise, respectively, a yellow, a magenta,and a cyan dye developer, each of said dye developers, having a hightransmittance over approximately two-thirds of the visible spectrum, anda high absorption in the remaining one-third.

Where such dye developers are initially colored and respectiveassociated dye developers, it is obvious that the amount of actinicenergy necessary to accom lish suitabIe excitation of the sensitizedsilver halide crystals contained within said emulsion is substantallyincreased.

The resultant effect of the dye developers absorption of a substantialproportion of the actinic energy available for silver halide crystalexcitation is necessarily a substantial decrease in the relative speedof the associated photosensitive emulsion.

As previously stated, in multicolor photographic processes, therespective preferred dye developers should theoretically absorb actinicradiation over a selected portion of the spectral range equal to thecolor absorption desired and further should exert no influence on and/orabsorption over the remaining portions of the spectrum. Thus, each dyedeveloper associated emulsion layer unit, comprising a multilayerphotosensitive element for use in obtaining multicolor images, shouldtheoretically absorb spectral radiation of a predelineated area of thespectral range. Therefore, in an integral multilayer photosensitiveelement which comprises three appropriately sensitized silver halideemulsions having associated therewith, respectively, a yellow, a magentaand a cyan dye developer, the preferred yellow dye developer should beone with relatively high absorption in the blue area of the spectrum andthus would affect or control only the amount of blue light passingthrough said dye developer, but would have substantially little, if any,influence on the passage of red or green light. The magenta dyedeveloper should be one with relatively high absorption in the greenarea of the spectrum and thus would affect and/ or control only theamount of green light passing through said dye developer but would havesubstantially little, if any, influence on the passage of red or bluelight. The cyan dye developer should be one with relatively highabsorption in the red area of the spectrum and thus would affect orcontrol only the amount of red light passing through said dye developerbut would have substantially little, if any, influence on the passage ofblue or green light.

Therefore, in an integral multilayer photosensitive element of the typepreviously described, upon exposure to actinic radiation comprising thevisible spectrum, said radiation preferably traversing through ablue-sensitive emulsion perpendicular to the plane of saidphotosensitive element, the respective yellow dye developer ordevelopers should theoretically absorb only the blue portion of thespectrum, thus allowing undiminished red and green wave lengths tocontact a subsequent green-sensitive magenta dye developer containingsilver halide emulsion. The magenta dye developer, in turn, shouldtheoretically absorb only the blue portion of the spectrum, thusallowing undiminished red and green wavelengths to contact a subsequentgreen-sensitive magenta dye developer containing silver halide emulsion.The magenta dye developer, in turn, should theoretically absorb only thegreen wavelengths of the spectrum and thus allow the red wavelengths tocontact, with undiminished energy, a subsequent red-sensitive cyan dyedeveloper containing silver halide emulsion. Many yellow, magenta andcyan dye developers exhibit substantial spectral absorption in areas ofthe spectrum other than their preferred theoretical areas.

The unavailability of dye developers with desired absorptioncharacteristics, that is, over one-third of the spectrum, and desiredtransmission characteristics, that is, over two-thirds of the spectrum,necessitates formulating a method of preand/or post-correcting of eachemulsion layer to avoid the loss of a substantial amount of actinicenergy upon exposure due to the undesirable absorption of the dyedeveloper associated emulsion layers through which the actinic radiationmust traverse in order to expose subsequent photosensitive emulsionlayers.

As disclosed in US. Pats. Nos. 3,307,947 and 3,336,287, issued Mar. 7,1967 and Aug. 15, 1967, it has been discovered that the necessity ofcorrecting or compensating for the aforementioned undesirableabsorption, that 13, internal absorption Within the respective emulsionlayer decreasing the speed of said emulsion, as well as decreasing theactinic radiation transmitted through said emulsion, may besubstantially obviated by effecting temporarily, that is, at least forthe duration of exposure of a photosensitive element, a hypsochromicshift of the absorption characteristics of the respective dye developerssuch that the absorption of said dye developers is rendered negligibleand transmission of the preferred spectral rays of light approximatesthe magnitude desired.

Dispersion of an associated dye developer in the photosensitive emulsiongenerally results in a substantial loss of the sensitivity of theemulsion due to the dye developer absorbing actinic energy in thecorresponding region of maximum emulsion sensitivity. This is apparentlydue to the fact that photographic dye developers associated with aphotosensitive silver halide emulsion generally possess a color, thatis, a spectral absorption curve, which is substantially the same as thatof the light, that is, the region of the spectrum, which the sensitizedemulsion is intended to record. In such instances, the dye developer hasits light absorption maximum, that is, k at a wavelength within themaximum sensitivity of the photosensitive emulsion with which it isassociated.

A hypsochromic shift of the light absorption spectrum of the respectivedye developer is preferred since the absorption bands of the dye falloff more sharply on the long wavelength side of the A A hypsochromicshift of the A approximately m susbtantially avoids absorption ofspectral energy by the respective dye developer in the spectral regionto which the associated emulsion is sensitized. However, it must benoted that a hypsochromic shift of the A approximating 20 to 30 m maysubstantially obviate the filtering effect of the respective dyedevelopers absorption on photosensitive emulsions in a rearward positionrequired by the conventional arrangement of integral multilayerphotosensitive elements.

It has now been discovered that the aforementioned temporary shift ofthe dye developers absorption characteristics may be attained by theutilization of monoand disazo dye developers wherein the bathochromiceffects of auxochromic hydroxy or amino substituted radicals substitutedat specific positions in relation to the azo configuration, have beentemporarily reduced by appropriately isolating said radicals frominteraction with the azo chromophore.

From the standpoint of the color of dyes, an auxochrome is best definedas a substituent atom or group which increases the intensity (6) of theabsorption of light due to a chromophore. An auxochrome may also shiftthe main absorption band (h to a longer wave length, just as a secondchromophore conjugated with the first increases the e in addition toshifting it to a longer h It must be noted, however, that a givenauxochrome may increase the s only for certain chromophores, and onlywhen it is situated in a suitable position with reference to saidchromophore, to thus form an auxochromophoric system. In anauxochromophoric system, it is believed that the absorption of lightresults from the electronic interaction between auxochromes andchromophores by which the contribution of highly conjugated andpolarized structures to the resonance of the dye molecule is increased.

Auxochromic hydroxyl and amino groups play a vital role in influencingthe absorption characteristics of the azo dye developers of thisinvention by reason of electronic interaction between the azochromophore and the respective hydroxyl or amino group. The position ofthe respective substituent in relation to the azo linkage largelydetermines the auxochromic effect, since resonance effects areinoperative in the meta position, auxochromic substituents are mainlyeffective in the ortho and para positions with respect to the azochromophore.

Diffusion-transfer reversal processes employing a photosensitiveelement, comprising not less than one silver halide emulsion havingassociated therewith not less than one image-forming component, shouldthus employ an image-forming component possessing a temporarily shiftedlight-absorption spectrum. The photosensitive element may be exposed toa predetermined actinic energy pattern and the resultant latent silverhalide image or images formed thereby developed in said emulsion oremulsions to effect, as a result of development, immobilization of therespective associated image-forming components in the exposed areas ofsaid photosensitive element which may be, at least in part, transferredby imbibition from the unexposed areas to a superposed image-receivinglayer. A non-reversible restoration of at least a portion of thetemporarily shifted image-forming components to their original spectralabsorption characteristics is effected, at some stage subsequent toexposure, so as to impart to the image-receiving layer a reversedpositive dye image of the latent image exhibiting the desired spectralabsorption characteristics.

It is a primary object of the present invention to provide novelphotographic diffusion transfer reversal processes and novel productsfor utilization therein.

Another object of the present invention is to provide novelphotosensitive elements, comprising not less than one silver halideemulsion and not less than one dye developer, possessing increasedemulsion speed and improved exposure control.

A further object of the present invention is to provide novelphotographic compounds, processes and products for obtaining colorimages by diffusion-transfer reversal processes, wherein the lightabsorption characteristics of the dye developers utilized to providesaid color images are temporarily shifted so that said dye developersabsorb actinic energy at wave lengths substantially shorter duringexposure than the wave lengths of the respective dye developersultimately desired.

A still further object of the present invention is to provide novelphotographic compounds, processes and products for obtaining colorimages by diffusion-transfer reversal processes, wherein the lightabsorption characteristics of the dye developers utilized to providesaid color images are temporarily shifted so that said dye developersabsorb actinic energy at wave lengths substantially shorter duringexposure than the wave lengths to which the dye developers associatedsilver halide emulsion is sensitized.

A still further object of the present invention is to provide novelphotographic compounds, processes and products for obtaining multicolortransfer images, using integral multilayers photosensitive elements,whereby unwanted absorption, that is, absorption at the wave lengths ofemulsion sensitization, is avoided.

A still further object of the present invention is to provide novelphotographic processes whereby temporarily shifted dye developers, thatis, dye developers the spectral absorption bands of which have beentemporarily shifted to lower wave lengths prior to exposure of aphotosensitive element containing said dye developers, may be restoredto their original spectral absorption characteristics subsequent toexposure of said photosensitive element.

A still further object of the present invention is to provide dyedevelopers, the spectral absorption characteristics of which aremodified to effect a temporary hypsochromic shift in the wave lengthsabsorbed during exposure of an associated photosensitive emulsion andwhich, subsequent to said exposure, may be restored to their originalabsorption characteristics.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the several steps and the relationand order of one or more of such steps with respect to each of theothers, and the product possess- 6 ing the features, properties and therelation of elements which are exemplified in the following detaileddisclosure, and the scope of the application of which will be indicatedin the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawing wherein:

FIG. 1 is a diagrammatic cross-sectional view of one embodiment of aphotographic product for use in obtaining monochromatic images inaccordance with this invention and comprising a photosensitive element,an imagereceiving element and a rupturable container holding aprocessing composition; and

FIG. 2 is a diagrammatic cross-sectional view of one embodiment of thisinvention, for use in obtaining multicolor images, during processing andcomprising a multilayer photosensitive element, an image-receivingelement and a processing composition.

The expression temporarily shifted dye developer as used herein isintended to signify a dye developer which has been modified chemicallyso that its spectral absorption bands have been relocated atsubstantially shorter Wave lengths, that is, a hypsochromic shift of theabsorption spectrum, for at least the time interval necessary toaccomplish photo-exposure of a photosensitive silver halide emulsionassociated therewith, and which dye developer is subject to restorationof the dye developers original absorption characteristics upon simplechemical treatment such as, for example, hydrolysis, methanolysis,ammonolysis, etc.

It has been taught in the aforementioned US. Pat. No. 3,307,947 that thepreviously characterized advantages achieved by the utilization oftemporarily shifted dye developers in photographic systems may beobtained by the employment of dye developers wherein specifiedauxochromic systems have undergone bathochromic shifts which result in achange in the electronic interaction between the respective auxochromesand chromophores. Alternation of the last-mentioned electronicinteraction between auxochromic hydroxyl or amino groups substituted inortho and/ or para position with respect to a chromophoric azo linkage,may be affected by any suitable technique, but a most preferred meanswas disclosed to be temporary acylation of the respective auxochromesubstituent or substituents. Restoration of the originalauxochromophoric system may be then readily secured by hydrolysis ofsuch acyl group by means of contact with an aqueous alkalinephotographic processing composition.

While the last-mentioned disclosed acylation of the selected auxochromicsubstituent does accomplish a hypsochromic shift in the spectralabsorption characteristics of the selected auxochromophoric system,where the selected auxochromic substituent comprises an amino groupsubstituted in ortho or para position with relation to a chromophoricazo linkage and/or a hydroxyl group substituted in para position to suchan azo linkage, it has additionally been taught in the above patent thatacylation of an auxochromic hydroxyl group substituted in ortho positionwith relation to a chromophoric azo linkage provides a hypsochromicshift of such extended magnitude as to be totally unexpected in view of,and unrelated in comparison with, the magnitude of hypsochromic shiftprovided the previously identified components.

As stated hereinbefore, a temporary hypsochromic shift of the dyedevelopers x at least for the period during which exposure of aphotographic :film unit retaining same is accomplished, constituting amagnitude of 20 to 30 11111., may be sufiicient to substantially avoid afiltering elfect, in the transmission of actinic energy to a rearwardlypositioned photosensitive emulsion, in many desired instances. Incertain instances, therefore, acylation of an auxochromic hydroxyl groupsubstituted para to a chromophoric azo linkage may be sufi'lcient toprovide the desired radiation absorptive characteristics to a givenphotographic film unit. In many instances, however, the maximummagnitude of such shift is considerably less than that desired toprovide the optimum radiation absorbing characteristics to the filmunit. In such circumstances, it is preferred that acylation of anauxochromic hydroxyl group substituted in ortho position with respect toa chromophoric azo linkage, in accordance with the present disclosure,be employed to provide the desired photographic optical properties.

The preferred group of dye developers, the spectral absorption curve ofwhich may be subjected to a temporary hypsochromic shift by isolation ofan appropriate auxochromic substituent, comprises monoand disazo dyedevelopers characterized in that they contain an auxochromic hydroxylgroup substituted on an aryl nucleus in ortho or ortho'ortho positionsto one or both azo linkages, that is, monoand disazo dye developerscharacterized in that said dye developers contain not less than one andnot more than two groups selected from the groups represented by theformulae:

( OH OH and said dye developers being further characterized in that theycontain not less than one and preferably not more than two groupsselected from the group consisting of pdihydroxyphenyl ando-dihydroxyphenyl groups and halogen and alkyl substituted derivativesthereof.

It will be apparent that preferred members of the aforementioned monoanddisazo dye developers may also be represented by the formulae:

wherein a is one or two; b is one or two; X is a p-dihydroxyphenyl or ano-dihydroxyphenyl group and the halogen and alkyl substitutedderivatives thereof; each Y represents the non-metallic atoms necessaryto complete an aryl nucleus, preferably a benzene or naphthalenenucleus, which aryl nuclei may be the same or different; and Zrepresents the residue of an azo coupler.

As examples of ortho-hydroxy and/ or ortho, orthodihydroxy substitutedmonoand disazo dye developers preferred for use in the practice of thepresent invention, mention may be made of the following:

2- (4'- [4"- (2',5 '-dihydroxyphenethyl) -phenylazo] naphthalene azo)-4-methoxy-1-naphthol p- 1-hydroxy-4methoxy-2-naphthalene azo)-phenethyl catechol 2- (p- [B- (hydroquinonyl) -ethyl] -phenylazo)-4-methoxyl-naphthol 2- (p- B- (hydroquinonyl -ethyl] -phenylazo-4-n-propoxyl-naphthol the preparations of which are disclosed in thecopending U.S. application of Elkan R. Blout, Milton Green, and

8 Howard G. Rogers, Ser. No. 612,045, filed Sept. 25, 1956, abandonedand replaced by Ser. No. 144,816, filed Oct. 18, 1961 (now U.S. Pat. No.3,134,672, issued May 26, 1964);

2-(2',5'-dimethoxy-4'- [p-(2",5"-dihydroxyphenyl)-phenylazo]-phenylazo)-4-methoxy-1-naphtho1 the preparation of which isdisclosed in the copending U.S. application of Helen P. Husek and MyronS. Simon, Ser. No. 612,054, filed Sept. 25, 1956, now abandoned andreplaced by Ser. No. 197,283, filed May 24, 1962 (now U.S. Pat. No.3,236,645, issued Feb. 22, 1966) and Ser. No. 197,259, filed May 24,1962 (now U.S. Pat. No. 3,134,763, issued May 26, 1954);

2-(2',5-dimethoxy-4-[p-2,5-dihydroxy phenethyl)-phenylazo]-phenylazo)-4-methoxy-l-naphthol the preparation of which isdisclosed in the copending U.S. application of Helen P. Husek, Ser. No.612,055, filed Sept. 25, 1956, now abandoned and replaced by Ser. No.192,355, filed May 4, 1962 (now U.S. Pat. No. 3,236,643, issued Feb. 22,1966) and Ser. No. 192,354, filed May 4, 1962 (now U.S. Pat. No.3,134,762, issued May 26, 1954);

2-p- [4'-methy1-2',5 -dihydroxyphenylthioethyl] phenylazo-4-methoxy-naphthol the preparation of which is disclosed in thecopending U.S. application of Milton Green and Howard G. Rogers, Ser.No. 633,905, filed June 6, 1957, now abandoned and replaced by Ser. No.193,326, filed May 8, 1962 (now U.S. Pat. No. 3,222,169, issued Dec. 7,1965);

2-(p-[2, '-dihydroxyphenoxy]-phenylazo)-4-methoxyl-naphthol thepreparation of which is disclosed in the copending U.S. application ofMilton Green, Ser. No. 680,403, filed Aug. 26, 1957, now abandoned;

2- (p- [hydroquinonylsulfonyl) -phenylazo] -4-methoxyl-naphthol thepreparation of which is disclosed in the copending U.S. application ofMilton Green, Ser. No. 680,434, filed Aug. 26, 1957, now abandoned andreplaced by Ser. No. 230,287, filed Oct. 12, 1962 (now U.S. Pat. No.3,230,086, issued Jan. 18, 1966);

2-(4'- [p-(hydroquinonyl) -phenylcarboxamido)-phenylazo]-4-methoxy-1-naphthol the preparation of which is disclosed inthe copending U.S. application of Milton Green, Ser. No. 703,515, filedDec. 18, 1957, now abandoned;

4,4-bis-(4"-[2",5'"-dihydroxyphenethyH-phenylsulfamyl)-l-hydroxy-1,2'-azonaphthalene4-(4-[2",5-dihydroxyphenethyl]-N-methyl-phenylsu1famyl)-2-(2',5-dimethoxyphenylazo)-1-naphtho1 the preparations of which aredisclosed in the copending U.S. application of Elkan R. Blout, MiltonGreen, Howard G. Rogers, and Robert B. Woodward, Ser. No. 707,- 109,filed Jan. 6, 1958, now abandoned;

2- 4'- [4- (2",5'-dihydroxyphenethyl -phenylcarbamyl] -pheny1azo)-4-methoxy-1-napl1thol the preparation of which is disclosed in thecopending U.S. application of Milton Green and Howard G. Rogers, Ser.No. 748,145, filed July 14, 1958, now abandoned and replaced by Ser. No.190,804, filed Apr. 27, 1962 (now U.S. Pat. No. 3,186,982, issued June1, 1965); and

1-(4-[2",5"-dihydroxyphenethyl]-2'-hydroxyphenylazo)- 2-naphthol thepreparation of which is disclosed in the copending U.S. application ofMilton Green and Myron S. Simon, Ser. No. 788,893, filed Apr. 15, 1964,now abandoned and replaced by Ser. No. 359,998, filed Apr. 15, 1964 (nowU.S. Pat. No. 3,299,041, issued Jan. 17, 1967).

In compounds comprising the last-mentioned class of dye developers, theauxochromic hydroxyl group may be selectively isolated from interactionwith the azo chromophore by acylation of said hydroxyl group accordingto the following procedure, in order to provide the preferred dyedevelopers for use in the practice of the present invention. These dyedevelopers comprise novel monoand disazo dye developers characterized inthat said dye developers contain not less than one and not more than twogroups of the formula:

ortho to at least one azo group, and not more than one of said groups isortho to the same nitrogen atom of said azo group; and which dyes mayalso be characterized in that they contain not less than one and notmore than two groups represented by the formulae:

wherein each R is an alkyl group, preferably a lower alkyl of from oneto ten carbon atoms, more preferably one to eight, such as methyl,ethyl, propyl, butyl, octyl, etc.; and said dye developers being furthercharacterized in that they contain not less then one and preferably notmore than two groups selected from the group consisting of ap-dihydroxyphenyl an o-dihydroxyphenyl group.

'It has been discovered that the compounds within the aforementionedformulae may be prepared by oxidizing to the quinone, thep-dihydroxyphenyl or o-dihydroxyphenyl groups, or derivatives thereof ofmonoor disazo dyes, said dyes characterized in that they contain notless then one and not more than two ortho-hydroxyazo and/ or ortho,ortho'-dihydroxyazo configurations, and said dyes being furthercharacterized in that they contain not less than one and not more thantwo groups selected from the group consisting of p-dihydroxyphenyl ando-dihydroxyphenol groups, including specifically the halogen and alkylsubstituted derivatives thereof; said oxidation being accomplished, forexample, with an oxidizing agent such as benzoquinone, chloranil, etc.;acylating the hydroxyl, groups substituted ortho and/ or ortho to one ormore azo groups by reacting the oxidation product with an acylatingagent of the formula:

said acylation being accomplished under anhydrous conditions.

Preferably, a solvent is employed, such .as chloroform, carbontetrachloride, methylene chloride, and the like. Optionally, potassiumcarbonate is employed to remove any hydrochloric acid that may be formedduring the process. It is critical, however, that rigidly anhydrousconditions be maintained.

The p-dihydroxyphenyl group or o-dihydroxyphenyl group or derivativesthereof, are regenerated by, subsequent to acylation, reduction, saidreduction being accomplished, for example, with a reducing agent such asxylohydroquinone or hydrogen in the presence of a suit able catalyst,such as a palladium/charcoal catalyst.

It is contemplated, within the scope of this invention that, wheredesirable, the dyes may contain one or more hydroxyl groups substitutedthereon in addition to those previously mentioned. Under suchconditions, the acylation action may be continued until substantiallycomplete acylation is attained, that is, acylation of each free hydroxyl group of the respective dye molecules.

As illustrative examples of the preferred alkoxy acetyl chlorideacylation agents within the scope of the present invention mention maybe made of:

methoxy acetyl chloride ethoxy acetyl chloride propoxy acetyl chloridebutoxy acetyl chloride octyloxy acetyl chloride isopropoxy acetylchloride isobutoxy acetyl chloride It will be recognized, from thepreceding discussion that, within the scope of the invention claimed,the alkyl group represented by the term R is intended to encompass theequivalents thereof, and, accordingly may comprise a substituted alkylor aliphatic group which may be saturated or unsaturated, in accordancewith the specific acylating agent optionally chosen to conform to thedesires of the operator.

The novel dye developers of the present invention provide advantagesover prior art compositions. For example, more complete hydrolysis ofthe dye is achieved in the positive image thus insuring a truer color.In addition, a relatively short induction time is required and a greaterdye transfer is exhibited as well as a more effective silverdevelopment. As will be seen in the following example, it is possible touse the dye developer of the present invention in the gelatin emulsionlayer in addition to coating it on an emulsion layer. Prior to thepresent invention, dye developers have not been as suitable for use inthe emulsion phase.

With specific regard to the p-dihydroxyphenyl and o-dihydroxyphenylgroups, or radicals, the remaining hydrogen atoms in the phenyl ringsystem may be suitably substituted by hydroxyl groups, amino groups,alltyl groups, or halogen atoms such as chloride and bromide atoms, andthe like, which do not interfere with the photographic silver halidedeveloping characteristics of the specified dihydroxyphenyl ring system.

In accordance with the present invention, it is contemplated to utilizea temporarily shifted dye developer and, specifically, a dye developerof the class detailed hereinbefore, in both monochromatic and multicolordiffusiontransfer reversal processes. It is contemplated to use at leastone of the dye developers employed in multicolor diffusion-transferreversal processes in the form of a temporarily shifted dye developer.Significant improvements may result from the use of even one temporarilyshifted dye developer in a multicolor process. It is also contemplatedto employ a plurality of temporarily shifted dye developers containingvarying modifying groups to effect temporary shift of the respective dyedevelopers spectral characteristic.

The novel temporarily shifted dye developers of the present inventionalso find extensive application in sub- 1 1 tractive color correctionprocesses, such as the integral masking procedures utilizing temporarilyshifted dye developers.

FIG. 1 of the accompanying drawing illustrates one method of processinga silver halide emulsion to obtain a monochromatic transfer image inaccordance with this invention. A photosensitive element 22 comprises asupport 20, a layer 16 containing a temporarily shifted dye developer,and a silver halide emulsion. As shown in the particular embodimentdepicted in FIG. 1, the photosensitive element 22 is shown in aspread-apart relationship (as, for example, during exposure) with animage-receiving element 24 having mounted thereon a rupturable container14 holding a processing composition. The imagereceiving element 24comprises a support and an image-receiving layer 12. After exposure, theimage-receiving element 24 is brought into superposed relationship withphotosensitive element 22, rupturable container 14 is ruptured byapplication of suitable pressure, for example, by advancing between apair of rolls (now shown), and a layer of the liquid processingcomposition is spread between the superposed elements. The processingcomposition permeates the silver halide emulsion and develops a latentimage contained therein. Subsequent to exposure, the temporarily shifteddye developer is restored to its original spectral absorptioncharacteristics. In unexposed areas, the dye developer will transfer tothe superposed image-receiving element 24, to constitute thereon apositive dye image in terms of exposure, said image exhibiting thespectral absorption characteristics of the desired restored dyedeveloper. The image-receiving element 24 is separated from itssuperposed relationship with the photosensitive element 22 after atleast a portion of the dye developer has been transferred.

It should be noted that it is within the scope of the present inventionto form images which comprise mixtures of temporarily shifted dyedevelopers and nonshifted or restored dye developers. The restoration ofthe respective dye developers original spectral absorptioncharacteristics may be effected by reacting said dye developer with oneor more processing compositions, subsequent to photoexposure, but priorto, concurrent with or subsequent to photographic processing. Ifdesired, an image-receiving element containing a transferred dyedeveloper may be contacted with said process-compositions subsequent todissociation of said image-receiving element from its superposedrelationship to the photosensitive element. For example, a temporarilyshifted esterified dye developer retained in an image-receiving element,may be subjected to caustic hydrolysis by contact with a secondprocessing composition prior to or subsequent to the aforementioneddissociation to provide an increased quantity of hydrolyzed dyedeveloper therein.

In the following examples, all parts are given by weight except whereotherwise noted and all operations involving light-sensitive materialsare carried out in the absence of actinic radiation. These examples areintended to be illustrative only of the synthesis and employment oftemporarily shifted dye developers wherein, subsequent to photoexposure,at least a portion of said temporarily shifted dye developer is restoredto the desired subtractive color absorption spectrum to provide areversed positive transfer image of the photographed subject and shouldnot be considered as limiting the invention in any way.

EXAMPLE 1 10 .gm. of 2-(p-[B(hydroquinonyl)-ethyl]phenylazo]-4-methoxy-l-naphthol, the preparation of which is disclosed in theaforementioned copending US. application Ser. No. 612,045, abandoned andreplaced by Ser. No. 144,816, filed Oct. 18, 1961 (now US. Pat. No.3,134,672, issued May 26, 1964) and 10.5 gm. of benzoquinone are 1 2refluxed for 3.5 hours in 150 cc. of chloroform to provide 3 gm. of

4-methoxy 2 (p-[B(p-quinonyl)-ethyl]-phenylazo)-lnaphthol.

EXAMPLE 2 8 gm. (.02 M) of dry 4-methoxy-2-(p [B-(p-quinonyl)ethyl]-phenylazo-1-naphthol are warmed under anhydrous conditions in ml.of freshly purified chloroform. 8 g. (.058 M) of anhydrous potassiumcarbonate are added and the mixture brought to reflux, 3.6 ml. (.029 M)of ethoxy acetyl chloride are added and refluxing continued for 48hours. Another 8 g. of potassium carbonate, and 3.6 ml. of ethoxy acetylchloride are added, and refluxing continued for four days. The reactionis cooled and filtered under slightly reduced pressure, and then thesolvent is removed under vacuum. The resulting hot orange-red oil istreated with 200 ml. of boiling hexane, and, from the quickly decantedsolvent, the product is filtered off and washed with hexane to removeunreacted acid chloride. The product is dissolved in 100 ml. of drybenzene by boiling, 50 ml. of hot hexane is added and mixed quickly toprecipitate the product as a red-brown oil. Precipitation is repeatedtwice to provide 4.3 g. of the product:

which melted at 132133 F.

EXAMPLE 3 3.6 g. of the product of Example 2 was reduced at atmosphericpressure in 100 ml. of ethyl acetate using 10% palladium barium sulfatecatalyst. At 27 F., the material took up the calculated volume ofhydrogen in 12 minutes. The product, 4methoxy-Z-[p-(B-hydroquinonylethyl)- phenylazo]-naphthalene-l-ethoxyacetate was recrystallized from boiling benzene in an 84% yield. Theproduct melted at 123-125 F. and exhibits a spectral absorption curvewhich displays a A at 397 m in methyl cellulose, e=15,200.

EXAMPLE 4 310 gm. of dry 4-isopropoxy-2-[p-(B-quinonyl-ethyl)-phenylazoJ-l-naphthol and 218 gm. of ethoxy acetyl chloride in 3 1.carbon tetrachloride were refluxed for 60 hours under anhydrousconditions. The product, 4-isopropoxy- 2 [p (B-quinonylethyl) phenylazo]naphthalene-1- ethoxy acetate, is separated and purified by ethylacetatehexane crystallization, to yield 178 gm. of the product whichmelted at 119-120 F., and exhibited a spectral absorption curve whichdisplays a h at 341 m in acetone; e=18,600.

13 EXAMPLE Employing the procedure of Example 4, substituting octyloxyacetyl chloride for ethoxy acetyl chloride,4-isopropoxy-2-[p-(B-quinonylethyl) phenylazo] naphthalene-l-octyloxyacetate was prepared having a melting point of 84-85 F. and exhibiting aspectral absorption curve which displays a A at 341 mg in methylcellulose; e=l9,400.

EXAMPLE 6 Employing the procedure of Example 4, substituting propoxyacetyl chloride for ethoxy acetyl chloride, 4- isopropoxy 2[p-(B-quinonylethyl)-phenylazo]-naphthalene-l-propoxy acetate wasprepared.

EXAMPLE 7 Employing the procedure of Example 4, substituting butoxyacetyl chloride for ethoxy acetyl chloride, 4-is0 propoxy 2[p-(B-quinonylethyD-phenylazo]-naphalenel-butoxy acetate was prepared.

EXAMPLE 8 A photosensitive element was prepared as follows: 5.0 g. of4-methoxy 2 [p-(B-hydroquinonylethyl)-phenylazo]-naphthalene-1-ethoxyacetate was dissolved in 7.5 cc. of diethyl decanamide and 5.0 cc. oftriethyl phosphite. This solution was emulsified by means of a highshear mechanical agitator, with an aqueous solution of 33.3 g. ofgelatin and a dispersing agent and then coated upon a subcoated filmbase with a green sensitive silver iodobromide emulsion and allowed todry. This photosensitive element was exposed and processed by spreading,between the thus exposed photosensitive element and a superposedimage-receiving element, an aqueous processing composition comprising:

Waterl00 cc.

Potassium hydroxide-11.2 g. Hydroxyethyl cellulose-3.8 g.Benzotriazole--3.5 g. N-benzyl-a-picoliniurn bromide-2.0 g.

The image-receiving element comprised baryta paper coated with a layerof a partial butyl ester of poly-(ethylene/maleic anhydride), followedby a layer of polyvinyl alcohol and a layer of 2:1 mixture, by weight,of polyvinyl alcohol and poly-4-vinyl pyridine. Image-receiving elementsof this type are disclosed and claimed in the copending aplication ofEdwin H. Land, Ser. No. 234,864, filed Nov. 1, 1962 (now U.S. Pat. No.3,362,819, issued Jan. 9, 1968).

After an imbibition period of aproximately one minute, theimage-receiving element was separated and contained a magenta positivedye image having a D of 2.18 and a 1 m Of 0.2.

EXAMPLE 9 A photosensitive element was prepared by coating a gelatinsubcoated film base with a solution comprising 0.3 g. of4-rnethoxy-2-[p-(B-hydroquinonylethyl)-phenylazo]-naphthalene-1-ethoxyacetate which was dissolved in 7.5 cc. of 2% cellulose acetate hydrogenphthalate in acetone. After this coating dried, a green-sensitive silveriodobromide emulsion was coated thereupon and allowed to dry. Thisphotosensitive element was exposed and processed as described in Example8.

After an imbibition period of approximately one minute, theimage-receiving element was separated and contained a magenta positiveimage having a D,,,,,,, of 2.52 and a D of 0.4.

14 EXAMPLE 10 A photosensitive element was prepared as follows: 1.0 g.of4-isopropoxy-2-[p-(B-hydroquinonylethyl)-phenylazo]-naphthalene-1-propoxyacetate was dissolved in 2 cc. of diethyl decanamide. This solution wasemulsified by means of a high shear mechanical agitator, with an aqueoussolution of 6.65 g. of 15% gelatin and then coated upon a subcoated filmbase, mixed with a green-sensitive silver iodobromide emulsion andallowed to dry. This photosensitive element was exposed and processed asdescribed in Example 8.

After an imbibition period of approximately one minute, theimage-receiving element was separated and contained a magenta positiveimage having a D of 1.56 and a Dmln. of 0.09.

EXAMPLE 11 A photosensitive element was prepared by coating a gelatinsubcoated film base with a solution comprising 0.22 g. of4-isopropoxy-2-[p-(B-hydroquinonylethyl)-phenylazo]-naphthalene-1-propoxyacetate which was dissolved in 5 cc. of 2% cellulose acetate hydrogenphthalate in acetone. After this coating dried, a green-sensitive silveriodobromide emulsion was coated thereupon and allowed to dry. Thisphotosensitive element was exposed and processed as described in Example8.

After an imbibition period of approximately one minute, theimage-receiving element was separated and contained a magenta positiveimage having a D of 1.23 and a D of 0.21.

EXAMPLE 12 A photosensitive element was prepared by coating a gelatinsubcoated film base with, a solution comprising 0.22 g. of4-isopropoxy-2-[p-(B-hydroxyquin0nylethyl)-phenylazo]-naphthalene-1-butoxy acetate which was dissolved in 5 cc. of2% cellulose acetate hydrogen phthalate in acetone. After this coatingdried, a green-sensitive silver iodobromide emulsion was coatedthereupon and allowed to dry. This photosensitive element was exposedand processed as described in Example 8.

After an imbibition period of approximately one minute, theimage-receiving element was separated and contained a magenta positiveimage having a D of 0.94 and a D of 0.25.

EXAMPLE 13 A photosensitive element was prepared by coating a gelatinsubcoated film base with a solution comprising 0.22 g. of4-methoxy-2-[p-(B-hydroquinonylethyl)-phe-nylazo]-naphthalene-1-octyloxyacetate which was dissolved in 5 cc. of 2% cellulose acetate hydrogenphthalate in acetone. After this coating dried, a green-sensitive silveriodobromide emulsion was coated thereupon and allowed to dry. Thisphotosensitive element was exposed and processed as described in Example8.

After an imbibition period of approximately one minute, theimage-receiving element was separated and contained a magenta positiveimage having a Dmax, of 0.66 and a D of 0.23.

As previously stated, the novel dye developers of the present inventionunexpectedly provide advantageously shorter photoexposed silver halidedevelopment induction times than those capable of being achievedemploying dye developers of the prior art. Thus increased dye transferimage definition control is provided by means of the present invention,which is especially preferred to provide the integrity of separate colorimage records which enhances the multicolor image acuity to be obtainedfrom multicolor transfer processes.

Such decreased development induction periods are readily illustrated byreference to the following tabular compilation, which details, forcomparative purposes, the induction periods obtained employingrepresentative dye developers of the present invention directly comparedwith representative dye developers of the prior art.

TABLE I developer in or behind the silver halide emulsion portion. Ingeneral, a suitable photosensitive screen, prepared in Dye developerControl. 4-methexy-2-[p-(B-hydroquinony1ethyl)-phenylazo]-naphthalene-l-acetate.

Test 4-methoxy-2[p-( B-hydroquinonylethyl)-phenylazo]-naphtl1-alcne-l-ethoxy acetate.

Control..... 4-itsopropoxy-2-[p-(B-hydroquinonylethyl)-phenylazo]-naphalene-l-acetate.

Test 4-isopropoxy-2-[p-(B-hydroquinonylcthyl)-phcnylazo]-naphthalene-l-ethoxy acetate.

Test .do

In addition, more complete hydrolysis of the dye forming the transferimage, as compared with image dyes of the prior art, is advantageouslyprovided employing the dye developers of the present invention as isreadily illus- The dye developers of the present invention alsounexpectedly provide, compared with prior art compounds, increased dyetransfer image maximum density, decreased dye transfer image minimumdensity, and more effective and efficient silver development, asdirectly illustrated in accordance with the disclosures of thelast-mentioned copending applications, comprises minute red-sensitizedemulsion elements, minute green-sensitized emulsion elements and minuteblue-sensitized emulsion elements arranged in side-by-side relationshipin a screen pattern and having associated therewith, respectively, acyan dye developer, a magenta dye developer and a yellow dye developer.

Another process for obtaining multicolor transfer images utilizing dyedevelopers employs an integral multilayer photosensitive element such asis disclosed and claimed in the copending US. application of Edwin H.Land and Howard G. Rogers, Ser. No. 565,135 (now US. Pat. No. 3,345,163,issued Oct. 3, 1967) wherein at least two selectively sensitizedphotosensitive strata are superposed on a single support and areprocessed, simultaneously and without separation, with a single, commonimage-receiving layer. A suitable arrangement of this type comprises asupport carrying a red-sensitive silver halide emulsion stratum, agreen-sensitive silver halide emulsion stratum and a blue-sensitivehalide emulsion stratum, said emulsions having associated therewith,respectively, a cyan dye developer, a magenta dye develthe followingtabular compilation of experimental results. oper and a yellow dyedeveloper. The dye developer may TABLE III Example Silver fabricatedimage Fog silver and optical optical Conceuprocessed density densitytratlon in accordof photoin photoof dye ance sensitive sensitive Dyedeveloper developer with- Dm Dmix element 1 element 1 Control4-isopropoxy-2-[p-(B-hydroquinonylethyl)- 0.38 9 0.75 0. 54 0.89 0. 61

phenylazo]-naphthalene-l-acetate. Testi-isopropoxy-zlp-(B-hydroquinonylethyl)- 0. 12 9 1. 22 0. 49 1. 18 0. 73

phenylazol-naphthalene-l-ethoxy acetate.

1 seconds development time.

It is also contemplated to utilize in the preparation of monochromaticimages, a film structure wherein the photo-sensitive element is coatedover the image-receiving layer and the processing composition mustpermeate through the emulsion before reaching the image-receiving layer.A structure of this type is described, for example, in U.S. Pat. No.2,661,293, issued to Edwin H. Land on Dec. 1, 1953, and particularlywith respect to FIG. 7 of said patent.

Multicolor images may be obtained using dye developers inditfusion-transfer reversal processes by several techniques. One suchtechnique contemplates the use of a photosensitive silver halide stratumcomprising at least two sets of selectively sensitized minutephotosensitive elements arranged in the form of a photosensitive screen.Transfer processes of this type are disclosed in the copending U.S.application of Howard G. Rogers, Ser. No. 748,421 (now U.S. Pat. No.2,983,606, issued May 9, 1961), and also in the copending US.application of Edwin H. Land, Ser. No. 448,441, filed Aug. 9, 1956 (nowUJS. Pat. No. 2,968,554, issued Jan. 17, 1961). In such an embodiment,each of the minute photosensitive elements has associated therewith anappropriate dye be utilized in the silver halide emulsion layer, forexample, in the form of particles, or it may be employed as a layerbehind the appropriate silver halide emulsion strata. Each set of silverhalide emulsion and associated dye developer strata may be separatedfrom other sets by suitable interlayers, for example, by a layer ofgelatin and/ or polyvinyl alcohol.

A multilayer photosensitive element of this type just described isillustrated in FIG. 2 of the accompanying drawing and is depicted duringprocessing. An exposed photosensitive element 60 comprises: a support58; a layer 54 containing a cyan dye developer and a redsensitive silverhalide emulsion; a layer 50 of a magenta dye developer exhibiting atemporarily shifted spectral absorption curve and a green-sensitivesilver halide emulsion; a layer 46 containing a yellow dye developer anda blue-sensitive silver halide emulsion. As noted above, each set ofsilver halide emulsion and associated dye developer strata may beseparated from other sets thereof by suitable interlayers (not shown),for example, by a layer of gelatin and/or polyvinyl alcohol. In certaininstances, it may be desirable to incorporate a yellow filter in frontof the green-sensitive emulsion and such yellow 17 filter may beincorporated in an interlayer. However, where desirable, a yellow dyedeveloper of the appropriate spectral characteristics and present in a.state capable of functioning as a yellow filter may be employed. In suchinstances, a separate yellow filter may be omitted.

Referring again to FIG. 2, a multilayer photosensitive element 60 isshown in processing relationship with an image-receiving element 62 anda layer 44 of a processing composition. The image-receiving element 62comprises a support 40 and an image-receiving layer 42. As noted inconnection with FIG. 1, the liquid processing composition is effectiveto initiate development of the latent image in the respective exposedsilver halide strata and also may effect restoration of the respectivetemporarily shifted magenta dye developer to its original absorptioncharacteristics. After a suitable imbibition period, during which atleast a portion of the dye developer associated with unexposed areas ofeach of said emulsions is transferred to the superposed image-receivingelement 62, the latter element may be separated to reveal the positivemulticolor image.

It should be noted that it is within the scope of this invention toutilize, in multicolor diffusion-transfer reversal processes, one ormore of the requisite dye developers in the form of temporarily shifteddye dewelopers. In certain instances, for example, it may be desirableto employ temporarily shifted dye developers in association with ared-sensitive and green-sensitive silver halide emulsion, together witha non-shifted dye developer associated with the blue-sensitive silverhalide emulsion.

The dye developers utilized in the processes of this invention may beincorporated in the photosensitive elements, for example, in, on, orbehind the respective silver halide emulsion. The dye developer may, forexample, be in a coating or layer behind the silver halide emulsion andsuch a layer or dye developer may be applied by the use of a coatingsolution containing about 0.5 to 8%, by weight, of the respective dyedeveloper. When the temporarily shifted dye developers, set forth inExamples 2 and 4, were placed in a dye carrier layer behind thegreen-sensitive emulsion in an integral multilayer photosensitiveelement of the type described in connection with FIG. 2, sensitivity ofthe rearwardly positioned red-sensitive emulsion was extendedapproximately 30mg into the shorter wave lengths of the spectrum, thatis, the sensitivity of the red-sensitive emulsion was extended fromapproximately 640mg down to approximately 610mg.

The liquid processing composition herein referred to comprises at leastan aqueous solution of an alkaline compound, for example, diethylamine,sodium hydroxide or sodium carbonate. If the liquid procesingcomposition is to be applied to the emulsion by being spread thereon,preferably in a relatively thin uniform layer, it may also include aviscosity-increasing compound constituting a film-forming material ofthe type which, when said composition is spread and dried, forms arelatively firm and relatively stable film. A preferred film-formingmaterial is a high molecular weight polymer such as a polymericwater-soluble other which is inert to an alkaline solution such as, forexample, a hydroxyethyl cellulose or sodium carboxymethyl cellulose.Other film-forming materials or thickening agent-s whose ability toincrease viscosity is substantially unaifected if left in solution for along period of time may also be used. The film-forming material ispreferably contained in the processing composition in suitablequantities to impart to said composition a viscosity in excess of 1,000centipoises at a temperature of approximately 24 C. and preferably ofthe order of 1,000 to 200,000 centipoises at said temperature.Illustrations of suitable liquid processing compositions may be found inthe several patents and copending applications herein mentioned and alsoin examples herein given. Under certain circumstances, it may bedesirable to apply a liquid processing composition to the photosensitiveelement prior to exposure, in accordance with the technique described inthe copending US. application of Edwin H. Land Ser. No. 498,672, filedApr. 1, 1955 (now US. Pat. No. 3,087,816, issued Apr. 30, 1963).

It will be noted that the liquid processing composition employed maycontain an auxiliary or accelerating developing agent, such asp-methylaminophenol, 2,4-diaminophenol, p-benzylaminophenol,hydroquinone, toluhydroquinone, phenylhydroquinone,4'-methylphenylhydroquinone, etc. It is also contemplated to employ aplurality of auxiliary or accelerating developing agents, such as3-pyrazolidone developing agent and a benzenoid developing agent, asdisclosed in US. Pat. No. 3,039,869, issued June 19, 1962. As examplesof suitable combinations of auxiliary developing agents, mention may bemade of l-phenyl-3-pyrazolidone in combination with pbenzylaminophenoland 1-phenyl-3-pyrazolidone in combination with2,5-bis-ethyleneimino-hydroquinone. Such auxiliary developing agents maybe employed in the liquid processing composition or they may beinitially incorporated, at least in part, in the silver halide emulsionstrata or the strata containing the dye developers. It may be noted thatat least a portion of the dye developer oxidized during development maybe oxidized and immobilized as a result of a reaction, e.g., anenergy-transfer reaction, with the oxidation product of an oxidizedauxiliary developing agent, the latter developing agent being oxidizedby the development of exposed silver halide. Such a reaction of oxidizeddeveloping agent with unoxidized dye developer would regenerate theauxiliary developing agent for further reaction with the exposed silverhalide.

In addition, development may be effected in the presence of an oniumcompound, particularly a quaternary ammonium compound, in accordancewith the processes disclosed in the copending U.S. application of MiltonGreen and Howard G. Rogers, Ser. No. 50,851, filed Aug. 22, 1960 (nowUS. Pat. No. 3,173,786, issued Mar. 16, 1965).

The dye developers are preferably selected for their ability to providecolors that are useful in carrying out subsractive color photography,i.e., cyan, magenta and yellow. It should be noted that it is within thescope of this invention to use mixtures of dye developers to obtain adesired color, e.g., black. This it is to be understood that theexpression color as used herein is intended to include the use of aplurality of colors to obtain black, as well as the use of a singleblack dye developer.

In all products employed in the practice of this invention, it ispreferable to expose from the emulsion side. It is, therefore, desirableto hold the photosensitive element and the image-receiving elementtogether at one end thereof by suitable fastening means in such mannerthat the photosensitive element and the image-receiving element may bespread apart from their superposed processing position during exposure.A camera apparatus suitable for processing film of the type justmentioned is provided by the Polaroid Land Camera, sold by PolaroidCorporation, Cambridge, Mass, or similar camera structure such, forexample, as the roll film-type camera forming the subject matter of U8.Pat. No. 2,435,717 or the film pack-type camera forming the subjectmatter of US. Pat. No. 2,991,702. Camera apparatus of this type permitssuccessive exposure of individual frames of the photosensitive elementfrom the emulsion side thereof as well as individual processing of anexposed frame by bringing said exposed frame into superposed relationwith a predetermined portion of the image-receiving element whiledrawing these portions of the film assembly between a pair of pressurerollers which rupture a container associated therewith and effect thespreading of the processing liquid released by rupture of saidcontainer, between and in contact with the exposed photosensitive frameand the predetermined, registered area of the image-receiving element.

The nature and construction of rupturable containers such as that shownin FIG. 1 is well understood in the art; see, for example, U.S. Pat. No.2,543,181, issued to Edwin H. Land on Feb. 27, 1951, and US. Pat. No.2,634,886, issued to Edwin H. Land on Apr. 14, 1953.

The image-receiving element comprises an imagereceiving layer of opaqueor transparent material which is liquid permeable and dyeable fromalkaline solutions and which has been illustrated for purposes ofsimplicity as comprising a single sheet of permeable material, forexample, paper. This element, however, may comprise a support upon whichat least one liquid-permeable and dyeable layer is mounted. The supportlayer may have a water-impermeable subcoat over which the stratum ofpermeable and dyeable material is applied. In certain instances, thedyeable layer may comprise a layer of liquid processing compositionwhich is adapted to remain adhered to the support layer upon stripping.

As examples of useful image-receiving materials, mention may be made ofnylon, e.g., N-methoxymethyl-polyhexamethylene adipamide, polyvinylalcohol, and gelatin, particularly polyvinyl alcohol or gelatincontaining a dye mordant such as poly-4-vinyl pyridine, and othermaterials of a similar nature, as is well known in the art. Theimage-receiving element also may contain a development restrainer, e.g.,l-phenyl-S-mercaptotetrazole, as disclosed in the copending applicationof Howard G. Rogers and Harriet W. Lutes, Ser. No. 50,849, filed Aug.22, 1960 now US. Pat. No. 3,265,498, issued Aug. 9, 1966.

While a rupturable container, such as container 14 in FIG. 1, provides aconvenient means for spreading a liquid processing composition betweenlayers of a film unit whereby to permit the processing to be carried outwithin a camera apparatus, the practices of this invention may beotherwise effected. For example, a photosensitive element, afterexposure in suitable apparatus and while preventing further exposurethereafter to actinic light, may be removed from such apparatus andpermeated with the liquid processing composition as by coating thecomposition on said photosensitive element or otherwise wetting saidelement with the composition following which the permeated, exposedphotosensitive element, still without additional exposure to actiniclight, is brought into contact with the image-receiving element forimage formation in the manner heretofore described.

It is also to be understood that the invention may be successfullypracticed without the use of a film-forming material in the liquidprocessing composition. As an illustration, a non-viscous liquidprocessing composition is particularly applicable with the processingtechnique last mentioned above and may be applied to the exposedphotosensitive element by imbibition or coating practices and may besimilarly applied to the image-receiving element before said elementsare brought into superposed relation or contact for carrying out thetransfer of nonimmobilized color-providing substances.

It will be apparent that the relative proportions of the agents of thediffusion transfer processing composition may be altered to suit therequirements of the operator. Thus, it is within the scope of thisinvention to modify the herein described developing compositions by thesubstitution of addition of preservatives, alkalis, silver halidesolvents, etc., other than those specifically mentioned. When desirable,it is also contemplated to include, in the developing composition,components such as restrainers, accelerators, etc. Similarly, theconcentration of various components may be varied over a wide range and,when desirable, adaptable components may be disposed in thephotosensitive element, prior to exposure, in a separate permeable layerof the photosensitive element and/or in the photosensitive emulsion.

In all examples of this specification, percentages of components aregiven by weight unless otherwise indicated.

Throughout the specification the expression positive image has beenused. This expression should not be interpreted in a restrictive sensesince it is used primarily for purposes of illustration, in that itdefines the image produced on the image-carrying layer as beingreversed, in the positive-negative sense, with respect to the image inthe photosensitive element. As an example of an alter- 'native meaningfor positive image, assume that the photosensitive element is exposed toactinic light through a negative transparency. In this case, the latentimage in the photosensitive element will be a positive and the imageproduced on the image-carrying layer will be a negative. The expressionpositive image is intended to cover such an image produced on theimage-carrying layer.

The dye developers of this invention may be used also in conventionalphotographic processes, such as tray or tank development of conventionalphotosensitive films, plates or papers to obtain black and white,monochromatic or toned prints or negatives. By way of examples, adeveloper composition suitable for such use may comprise an aqueoussolution of approximately 1 to 2% of the dye developer, 1% sodiumhydroxide, 2% sodium sulfite and 0.05% potassium bromide. Afterdevelopment is completed, any unreacted dye developer is washed out ofthe photosensitive element, preferably with an alkaline washing mediumor other medium in which the unreacted dye developer is soluble. Theexpression toned is used to designate photographic images wherein thesilver is retained with the precipitated dye, whereas monochromatic isintended to designate dye images free of silver.

Since certain changes may be made in the above product and processwithout departing from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawing shall be interpreted as illustrative and not ina limiting sense.

What is claimed is:

1. A process of forming transfer images in color which comprises thesteps of exposing a photosensitive element containing a silver halideemulsion and a dye selected from the group consisting of monoand disazodyes which contain not less than one and not more than two groupsselected from the group represented by the formulae:

wherein each R represents a lower alkyl group and Y represents the atomsnecessary to complete an aryl group and Z represents the residue of anazo dye coupler; said dyes further characterized in that they containnot less than one and not more than two dihydroxyphenyl silver halidedeveloping radicals; permeating said photosensitive element with anaqueous alkaline processing composition, elfecting therebysolubilization of said dye, and deacylation of said -CHr-O-R groups, byhydrolysis, to provide hydroxyl groups and thereby a dye selected fromthe group consisting of orthodihydroxyazo, and ortho,ortho'-dihydroxyazo monoand disazo dyes which contain not less than oneand not more than two dihydroxyphenyl silver halide developing radicals,thereby providing a nonreversible bathochromic shift of the spectralabsorption characteristics of said dye, and developement of said exposedsilver halide emulsion; immobilizing said dye as a result of developmentof the exposed areas of said emulsion and thereby forming an 21imagewise distribution of mobile dye, as a function of thepoint-to-point degree of exposure of said emulsion; and transferring, byimbibition, at least a portion of said imagewise distribution of dye toa superposed imagereceiving layer to provide thereto a positive dyeimage.

2. A process of forming transfer images in color as defined in claim 1,including the step of effecting said development in the presence of anadditional, accelerating silver halide developing agent.

3. A process of forming transfer images in color as defined in claim 1wherein said dye is 4-methoxy-2- [p-(flhydroquinonyl ethyl)phenylazo]-naphthalene-1-ethoxy acetate.

4. A process of forming transfer images in color as defined in claim 1wherein said dye is 4-isopropoxy-2- [p (B hydroquinonylethyl)-pheny1azo]-naphthalenel-ethoxy acetate.

5. A process of forming transfer images in color as defined in claim 1wherein said dye is 4-isopropoxy-2- [p-(fl-hydroquinonylethyl)-phenylazo1-naphthalene 1- octyloxy acetate.

6. A process of forming transfer images in color as defined in claim 1wherein said dye is 4-isopropoXy-2- [p-(B-hydroquinonylethyl)-phenylazo]-naphthalene 1- propoxy acetate.

7. A process of forming transfer images in color as defined in claim 1wherein said dye is 4-isopropoxy-2- [p-(fi-hydroquinonylethyl)-phenylazo1-naphthalene 1- butoxy acetate.

8. A photographic product which comprises a plurality of layers, atleast one of said layers comprising a silver halide emulsion, at leastone of said layers containing dye selected from the group consisting ofmonoand disazo dyes which contain not less than one and not more thantwo groups selected from the groups represented by the formulae:

wherein each R represents a lower alkyl group and Y represents the atomsnecessary to complete an aryl group and Z represents the residue ofanazo dye coupler; and said dyes further characterized in that theycontain not less than one and not more than two dihydroxyphenyl silverhalide developing radicals.

9. A product as defined in claim 8 wherein said dye is 4 methoxy 2-[p-(fi-hydroquinonyl ethyl)-pheny1azo]- naphthalene-l-ethoxy acetate.

10. A product as defined in claim 8 wherein said dye is4-isopropoxy-2-[p-(B-hydroquinonyl ethyl)-phenylazo]-naphthalene-l-ethoxy acetate.

11. A product as defined in claim 8 wherein said dye is4-isopropoxy-2-[p-(fi-hydroquinonyl ethyl) -phenylazo]-naphthalene-1-octyloxy acetate.

12. A product as defined in claim 8 wherein said dye is4-isopropoxy-2-[p-(B-hydroquinonyl ethyl)-phenylazo]-naphthalene-l-propoxy acetate.

13. A product as defined in claim 8 wherein said dye is4-isopropoxy-2-[p-(fi-hydroquinonyl ethyl)-phenylazo]-naphthalene-l-butoxy acetate.

References Cited UNITED STATES PATENTS 2,860,974 11/1958 Williams 96-92,983,606 5/ 1961 Rogers 96---29 3,307,947 3/ 1967 Idelson et a1.3,336,287 8/1967 Idelson et al.

NORMAN G. TORCHIN, Primary Examiner T. SURO PICO, Assistant Examiner

